Dynamics and control of towed vehicle for ocean measurementkeyword : towed vehicle, dynamics, control, ocean measurement1985.04A towed vehicle system, FLYING FISH, is under developing of use in making chemical and physical measurements with enable us to obtain specially continuous and real time data of current velocities, salinity, water temperature, dissolved O2, CO2, pH, chrolophill in an ocean mixed layer. The heave, pitch and roll of FLYING FISH are controlled by a main wing and horizontal tail wings which permit its stable attitudes and assure accurate measurements. The LQI-, H∞- and Gain scheduled-controller were designed, and the numerical simulation and field experiments were carried out. The picture shows the field experiment in Japan Sea.

Dynamics and control of AUV for ocean measurementkeyword : dynamics, conrol, AUV, ocean measurement1990.04Diving Beetle can be operated both as semi-long distance cruising underwater vehicle and a position controlled vehicle such as an ROV. The vehicle has 6 thrusters and horizontal tail Wings to control its cause and position..

Dynamic positioning system of floating structurekeyword : DPS, control, floating structure1994.04Offshore floating platforms are required to maintain its position within a given watch circle and to rectify this position under external forces of ocean current, wind and waves. A dynamic positioning system using thrusters is generally employed for this. In this system, it should be noted that motions caused by the linear wave exciting force are added to the drifting of the platform, the enormous amount of power is needed to resist the wave frequency motion and, in any event, this motion need not be controlled because of its small amplitude. Therefore, the objects of the controller are to control its position using thruster activity that do not respond to linear wave force.
Based on a rotation matrix in yaw, a linear model with four vertices was introduced. The problem was formulated in a framework of multi-model based design of H∞ control law with pole region constraint. LMI (linear matrix inequality)-based methodology was used to solve the problem. In another approach, a Neural Network Controller is designed. The picture shows and experiment in our ocean engineering tank(Length 65m, Breadth 5m, Depth 7m).

Mooring of ocena platformkeyword : mooring, buoy, ocean platform2000.04A new wave monitoring system"Compass" is developing to meet a need for measuring waves with good accuracy on floating structures such as large buoys, semi-submersible oil rigs and platforms operating in the ocean. In this system, the heaving response function of the floating structures is used to get the time history date and power spectrum of ocean waves. The first system is operating 40km off Iriomote Island of Okinawa..

Dynamics and control of ROVkeyword : dynamics, control, ROV1990.04An ROV developed for investigations of the sea bottom over a wide area can be operated both as a towed and a self-propulsive vehicle. Called DELTA, the shape is similar to that of a delta wing airplane. The vehicle has two-propellers and weight shift apparatus as actuators. The trim balance of DELTA can be achieved by weight shifting and direction is controlled by the thrust difference between the two propellers. The depth is altered by the trim angle and the forward speed, and course is adjusted by a direction control with the forward speed. The restoring torque caused by a combination of buoyancy and gravity force is expected to control roll. DELTA had roll, pitch and depth sensors to measure its attitudes. Length of the vehicles is 1.13m, displacement is 0.0525m3 and weight in the air is 54.7kg.
DELTA is being remodeled from an ROV to a non-tethered AUV..

Study on visual-feedbackkeyword : visual-feedback2002.04.

Dynamics and control of long flexible pipekeyword : long flexible pipe, dynamics, control2000.04.